The use of polyacrolein in antimicrobial applications has been described in U.S. Pat. No. 5,290,894, Australian Application 11686/95 and its European counterpart EP 667358, in our International patent publication WO 96/38186 (PCT/AU96/00328) and more recently we have described a method of improving the activity of acrolein polymers in our International patent publication WO 01/60874 (PCT/AU00/00107).
Many of the most stable compositions of polyacrolein or use as antimicrobials are formed by heating the polymer in air. Indeed Australian Application No 11686/85 (Werle et al assigned to Degussa) teaches that only those preparations dried using the process of the invention described therein with strong air current and final air temperatures of >60° C., preferably at 75° C. are alkali soluble.
Our International Publication WO 01/60874 describes a method of improving antimicrobial activity of acrolein polymers in which the solid polymers are oxidized in air and the oxidized polymers are heated in an alcohol solution in the presence of added alkali. The presence of carboxylic acid groups formed by oxidation in air is believed to improve the solubility of polyacrolein compositions. We have now found that polyacrolein polymer of high solubility; antimicrobial activity and stability may be formed without the requirement for this aerial oxidation step.